1. Field of the Invention
The present invention relates to a threaded member such as a bolt or nut made of fiber-reinforced plastic (FRP) having excellent screwing ability and to a method of producing the same. When the bolt and nut are screwed together, they are capable of being meshed smoothly with each other without shaking or jolting which may be caused if the bolt and nut do not have adequate fitness with respect to each other. They also have excellent weathering resistance and chemical resistance.
2. Description of the Prior Art
At the present time, threaded members such as a bolt or a nut made of FRP are endowed with corrosion resistance and electric insulating properties and are utilized to secure portions which are readily corroded, such as portions of chemical equipment and marine structures or portions which must be electrically insulated, such as in heavy electrical machines or electric trams. When the threaded surface of a threaded member made of FRP is formed by cutting, as compared with a metallic threaded member, it has inadequate fitness, inferior screwing accuracy and inferior weathering resistance and chemical resistance. Because the worked cut surface may be slightly exposed, a liquid such as water will readily penetrate into voids in the exposed cut surface which are formed near the glass reinforcing fibers. Further, short strips of glass fibers exposed on the cut surface may attach to the skin of human workers and cause irritation of the skin and an itching sensation. There has been a great need to solve these problems.